Field of the Invention
The present invention relates to a projection type video display such as a liquid crystal projector, and the like.
One of methods of utilizing the liquid crystal projector is to receive a video signal output from a personal computer and to project an image. That is, when a person who makes a presentation operates a personal computer and displays the image that the person intends participants of the presentation to see on a display of the personal computer, the same image as the above-described image is projected on a screen by the liquid crystal projector, so that all the participants can see the image. On the other hand, in some cases, the person who makes a presentation may not wish to show all the images which appear in the course of operating the computer to the participants. It is noted that there is a liquid crystal projector equipped with a shutter on a light-emission side of a light source (see Japanese Patent Application Laying-open No. 2002-365607).